The Luftwaffe used many ways to divert marauding Allied aircraft from their real targets. Putting dummy aircraft on false airfields was one of them. Sometimes they went very far in the realism of the dummies as these photo's show.

(Source: Messerschmitt "O-Nine" Gallery)

(Source: Flugzeug Archiv 8)

(Source: Jet & Prop Archiv 7)